<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>06.栅格系统的应用</title>
    <link rel="stylesheet" href="bootstrap-4.5.3/css/bootstrap.css">
    <style>
        div.a {
            background-color: red;

        }

        div.b {
            background-color: yellow;

        }
    </style>
</head>

<body>
    <!-- 需求 一行有三个
    container  有最大值限制 
    container-fluid  百分之百

    小屏幕和超小屏幕  一行1个格子
    col-
    col-sm
    中等   2个
    col-md
    大屏   3个
    col-lg
    超大   4个
    col-xl
    -->
    <div class="container">
        <div class="row">
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="a col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
            <div class="b col-12 col-sm-12 col-md-6 col-lg-4 col-xl-3">数据</div>
        </div> 
       
    </div> 



</body>

</html>